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The progressive decline of CD8 T cell effector function-also known as terminal exhaustion-is a major contributor to immune evasion in cancer. Yet, the molecular mechanisms that drive CD8 T cell dysfunction remain poorly understood. Here, we report that the Kelch-like ECH-associated protein 1 (KEAP1)-Nuclear factor erythroid 2-related factor 2 (NRF2) signaling axis, which mediates cellular adaptations to oxidative stress, directly regulates CD8 T cell exhaustion. Transcriptional profiling of dysfunctional CD8 T cells from chronic infection and cancer reveals enrichment of NRF2 activity in terminally exhausted (Texterm) CD8 T cells. Increasing NRF2 activity in CD8 T cells (via conditional deletion of KEAP1) promotes increased glutathione production and antioxidant defense yet accelerates the development of terminally exhausted (PD-1+TIM-3+) CD8 T cells in response to chronic infection or tumor challenge. Mechanistically, we identify PTGIR, a receptor for the circulating eicosanoid prostacyclin, as an NRF2-regulated protein that promotes CD8 T cell dysfunction. Silencing PTGIR expression restores the anti-tumor function of KEAP1-deficient T cells. Moreover, lowering PTGIR expression in CD8 T cells both reduces terminal exhaustion and enhances T cell effector responses (i.e. IFN-γ and granzyme production) to chronic infection and cancer. Together, these results establish the KEAP1-NRF2 axis as a metabolic sensor linking oxidative stress to CD8 T cell dysfunction and identify the prostacyclin receptor PTGIR as an NRF2-regulated immune checkpoint that regulates CD8 T cell fate decisions between effector and exhausted states.
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In cancer and infections, self-renewing stem-like CD8+ T cells mediate the response of immunotherapies and replenish terminally exhausted T cells and effector-like T cells. However, the programs governing the lineage choice in chimeric antigen receptor (CAR) T cells are unclear. Here, by simultaneously profiling single-cell chromatin accessibility and transcriptome in the same CAR T cells, we identified heterogeneous chromatin states within CD8+ T cell subsets that foreshadowed transcriptional changes and were primed for regulation by distinct transcription factors. Transcription factors that controlled each CD8+ T cell subset were regulated by high numbers of enhancers and positioned as hubs of gene networks. FOXP1, a hub in the stem-like network, promoted expansion and stemness of CAR T cells and limited excessive effector differentiation. In the effector network, KLF2 enhanced effector CD8+ T cell differentiation and prevented terminal exhaustion. Thus, we identified gene networks and hub transcription factors that controlled the differentiation of stem-like CD8+ CAR T cells into effector or exhausted CD8+ CAR T cells.
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Linfócitos T CD8-Positivos , Fatores de Transcrição , Fatores de Transcrição/genética , Subpopulações de Linfócitos T , Diferenciação Celular , CromatinaRESUMO
Immunotherapy has made a significant impact in many tumors, including renal cell carcinoma (RCC). RCC has been known to be immunoresponsive since the cytokine era of IFNα and IL2, but only a small number of patients had durable clinical benefit. Since then, discoveries of key tumor drivers, as well as an understanding of the contribution of angiogenesis and the tumor microenvironment (TME), has led to advances in drug development, ultimately transforming patient outcomes. Combinations of anti-angiogenic agents with immune checkpoint inhibitors are now standard of care. Current challenges include patient selection for immunotherapy combinations, resistance acquisition, and optimally sequencing therapies. Further discoveries about RCC biology, the TME, and resistance mechanisms will likely pave the way for the next generation of therapies.
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Carcinoma de Células Renais , Neoplasias Renais , Humanos , Carcinoma de Células Renais/tratamento farmacológico , Carcinoma de Células Renais/patologia , Neoplasias Renais/tratamento farmacológico , Neoplasias Renais/patologia , Imunoterapia , Fatores Imunológicos/uso terapêutico , Microambiente TumoralRESUMO
The recently identified G-protein-coupled receptor GPR171 and its ligand BigLEN are thought to regulate food uptake and anxiety. Though GPR171 is commonly used as a T cell signature gene in transcriptomic studies, its potential role in T cell immunity has not been explored. Here we show that GPR171 is transcribed in T cells and its protein expression is induced upon antigen stimulation. The neuropeptide ligand BigLEN interacts with GPR171 to suppress T cell receptor-mediated signalling pathways and to inhibit T cell proliferation. Loss of GPR171 in T cells leads to hyperactivity to antigen stimulation and GPR171 knockout mice exhibit enhanced antitumor immunity. Blockade of GPR171 signalling by an antagonist promotes antitumor T cell immunity and improves immune checkpoint blockade therapies. Together, our study identifies the GPR171/BigLEN axis as a T cell checkpoint pathway that can be modulated for cancer immunotherapy.
Assuntos
Imunidade , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Linfócitos T/metabolismo , Animais , Linhagem Celular Tumoral , Proliferação de Células , Células HEK293 , Humanos , Imunoterapia , Ligantes , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neoplasias/terapia , Neuropeptídeos/metabolismo , Receptores Acoplados a Proteínas G/deficiência , Transdução de SinaisRESUMO
Patients with activated phosphatidylinositol 3-kinase delta (PI3Kδ) syndrome (APDS) present with sinopulmonary infections, lymphadenopathy, and cytomegalvirus (CMV) and/or Epstein-Barr virus (EBV) viremia, yet why patients fail to clear certain chronic viral infections remains incompletely understood. Using patient samples and a mouse model (Pik3cdE1020K/+ mice), we demonstrate that, upon activation, Pik3cdE1020K/+ CD8+ T cells exhibit exaggerated features of effector populations both in vitro and after viral infection that are associated with increased Fas-mediated apoptosis due to sustained FoxO1 phosphorylation and Fasl derepression, enhanced mTORC1 and c-Myc signatures, metabolic perturbations, and an altered chromatin landscape. Conversely, Pik3cdE1020K/+ CD8+ cells fail to sustain expression of proteins critical for central memory, including TCF1. Strikingly, activated Pik3cdE1020K/+ CD8+ cells exhibit altered transcriptional and epigenetic circuits characterized by pronounced interleukin-2 (IL-2)/STAT5 signatures and heightened IL-2 responses that prevent differentiation to memory-like cells in IL-15. Our data position PI3Kδ as integrating multiple signaling nodes that promote CD8+ T cell effector differentiation, providing insight into phenotypes of patients with APDS.
Assuntos
Linfócitos T CD8-Positivos/enzimologia , Montagem e Desmontagem da Cromatina , Cromatina/metabolismo , Classe I de Fosfatidilinositol 3-Quinases/metabolismo , Memória Imunológica , Doenças da Imunodeficiência Primária/enzimologia , Transcrição Gênica , Viroses/enzimologia , Adolescente , Adulto , Animais , Apoptose , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Estudos de Casos e Controles , Criança , Cromatina/genética , Classe I de Fosfatidilinositol 3-Quinases/genética , Classe I de Fosfatidilinositol 3-Quinases/imunologia , Modelos Animais de Doenças , Ativação Enzimática , Proteína Ligante Fas/genética , Proteína Ligante Fas/metabolismo , Feminino , Células HEK293 , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças da Imunodeficiência Primária/genética , Doenças da Imunodeficiência Primária/imunologia , Transdução de Sinais , Viroses/genética , Viroses/imunologiaRESUMO
During chronic infection and cancer, a self-renewing CD8+ T cell subset maintains long-term immunity and is critical to the effectiveness of immunotherapy. These stem-like CD8+ T cells diverge from other CD8+ subsets early after chronic viral infection. However, pathways guarding stem-like CD8+ T cells against terminal exhaustion remain unclear. Here, we show that the gene encoding transcriptional repressor BACH2 is transcriptionally and epigenetically active in stem-like CD8+ T cells but not terminally exhausted cells early after infection. BACH2 overexpression enforced stem-like cell fate, whereas BACH2 deficiency impaired stem-like CD8+ T cell differentiation. Single-cell transcriptomic and epigenomic approaches revealed that BACH2 established the transcriptional and epigenetic programs of stem-like CD8+ T cells. In addition, BACH2 suppressed the molecular program driving terminal exhaustion through transcriptional repression and epigenetic silencing. Thus, our study reveals a new pathway that enforces commitment to stem-like CD8+ lineage and prevents an alternative terminally exhausted cell fate.
Assuntos
Infecções por Arenaviridae/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular , Epigênese Genética , Células Precursoras de Linfócitos T/metabolismo , Transcrição Gênica , Animais , Infecções por Arenaviridae/genética , Infecções por Arenaviridae/imunologia , Infecções por Arenaviridae/virologia , Fatores de Transcrição de Zíper de Leucina Básica/deficiência , Fatores de Transcrição de Zíper de Leucina Básica/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/virologia , Linhagem da Célula , Células Cultivadas , Doença Crônica , Modelos Animais de Doenças , Interações Hospedeiro-Patógeno , Vírus da Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/patogenicidade , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fenótipo , Células Precursoras de Linfócitos T/imunologia , Células Precursoras de Linfócitos T/virologia , Transdução de SinaisRESUMO
Progenitor-like CD8+ T cells mediate long-term immunity to chronic infection and cancer and respond potently to immune checkpoint blockade. These cells share transcriptional regulators with memory precursor cells, including T cell-specific transcription factor 1 (TCF1), but it is unclear whether they adopt distinct programs to adapt to the immunosuppressive environment. By comparing the single-cell transcriptomes and epigenetic profiles of CD8+ T cells responding to acute and chronic viral infections, we found that progenitor-like CD8+ T cells became distinct from memory precursor cells before the peak of the T cell response. We discovered a coexpression gene module containing Tox that exhibited higher transcriptional activity associated with more abundant active histone marks in progenitor-like cells than memory precursor cells. Moreover, thymocyte selection-associated high mobility group box protein TOX (TOX) promoted the persistence of antiviral CD8+ T cells and was required for the programming of progenitor-like CD8+ T cells. Thus, long-term CD8+ T cell immunity to chronic viral infection requires unique transcriptional and epigenetic programs associated with the transcription factor TOX.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Regulação da Expressão Gênica , Proteínas de Homeodomínio/genética , Infecções/etiologia , Análise de Célula Única , Animais , Biomarcadores , Imunoprecipitação da Cromatina , Epigênese Genética , Perfilação da Expressão Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Proteínas de Homeodomínio/metabolismo , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Memória Imunológica , Infecções/metabolismo , Coriomeningite Linfocítica/imunologia , Coriomeningite Linfocítica/virologia , Vírus da Coriomeningite Linfocítica/imunologia , Camundongos , Fatores de Tempo , TranscriptomaRESUMO
Chronic infection and cancer are associated with suppressed T cell responses in the presence of cognate antigen. Recent work identified memory-like CXCR5+ TCF1+ CD8+ T cells that sustain T cell responses during persistent infection and proliferate upon anti-PD1 treatment. Approaches to expand these cells are sought. We show that blockade of interferon type 1 (IFN-I) receptor leads to CXCR5+ CD8+ T cell expansion in an IL-27- and STAT1-dependent manner. IFNAR1 blockade promoted accelerated cell division and retention of TCF1 in virus-specific CD8+ T cells. We found that CD8+ T cell-intrinsic IL-27 signaling safeguards the ability of TCF1hi cells to maintain proliferation and avoid terminal differentiation or programmed cell death. Mechanistically, IL-27 endowed rapidly dividing cells with IRF1, a transcription factor that was required for sustained division in a cell-intrinsic manner. These findings reveal that IL-27 opposes IFN-I to uncouple effector differentiation from cell division and suggest that IL-27 signaling could be exploited to augment self-renewing T cells in chronic infections and cancer.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Autorrenovação Celular/imunologia , Interleucinas/metabolismo , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Animais , Anticorpos Monoclonais/farmacologia , Linfócitos T CD8-Positivos/virologia , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Fator 1-alfa Nuclear de Hepatócito/metabolismo , Memória Imunológica , Fator Regulador 1 de Interferon/genética , Fator Regulador 1 de Interferon/metabolismo , Interleucinas/genética , Coriomeningite Linfocítica/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Receptor de Interferon alfa e beta/antagonistas & inibidores , Receptores CXCR5/metabolismo , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismo , TranscriptomaRESUMO
T cell senescence and exhaustion are major barriers to successful cancer immunotherapy. Here we show that miR-155 increases CD8+ T cell antitumor function by restraining T cell senescence and functional exhaustion through epigenetic silencing of drivers of terminal differentiation. miR-155 enhances Polycomb repressor complex 2 (PRC2) activity indirectly by promoting the expression of the PRC2-associated factor Phf19 through downregulation of the Akt inhibitor, Ship1. Phf19 orchestrates a transcriptional program extensively shared with miR-155 to restrain T cell senescence and sustain CD8+ T cell antitumor responses. These effects rely on Phf19 histone-binding capacity, which is critical for the recruitment of PRC2 to the target chromatin. These findings establish the miR-155-Phf19-PRC2 as a pivotal axis regulating CD8+ T cell differentiation, thereby paving new ways for potentiating cancer immunotherapy through epigenetic reprogramming of CD8+ T cell fate.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Melanoma Experimental/imunologia , MicroRNAs/metabolismo , Neoplasias Cutâneas/imunologia , Fatores de Transcrição/metabolismo , Transferência Adotiva/métodos , Animais , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/transplante , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Senescência Celular/genética , Senescência Celular/imunologia , Epigênese Genética/imunologia , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Melanoma Experimental/genética , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/genética , Fosfatidilinositol-3,4,5-Trifosfato 5-Fosfatases/metabolismo , Complexo Repressor Polycomb 2/imunologia , Complexo Repressor Polycomb 2/metabolismo , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/terapia , Fatores de Transcrição/genética , Fatores de Transcrição/imunologiaRESUMO
The local environments within an amphiphilic polymer shell wrapped around lanthanide-doped upconverting nanoparticles were probed using steady-state and time-resolved fluorescence spectroscopy techniques. Emission lifetime measurements of pyrene chromophores trapped within the polymer shell reveal that there are at least two environments, where the organic pyrene molecules are encapsulated in hydrophobic environments that have lower polarity than in water. The migration of pyrene chromophores from their initial location to another location was also observed, demonstrating that the polymeric shell provides both hydrophobicity and mobility for entrapped molecules. These results offer insight into what outcomes can be expected when chemical reactions are carried out in these nanoassemblies, especially if they are to be used as nanoreactors for synthesis or delivery vehicles for therapeutics.
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mTOR has important roles in regulation of both innate and adaptive immunity, but whether and how mTOR modulates humoral immune responses have yet to be fully understood. To address this issue, we examined the effects of rapamycin, a specific inhibitor of mTOR, on B cell and CD4 T cell responses during acute infection with lymphocytic choriomeningitis virus. Rapamycin treatment resulted in suppression of virus-specific B cell responses by inhibiting proliferation of germinal center (GC) B cells. In contrast, the number of memory CD4 T cells was increased in rapamycin-treated mice. However, the drug treatment caused a striking bias of CD4 T cell differentiation into Th1 cells and substantially impaired formation of follicular helper T (Tfh) cells, which are essential for humoral immunity. Further experiments in which mTOR signaling was modulated by RNA interference (RNAi) revealed that B cells were the primary target cells of rapamycin for the impaired humoral immunity and that reduced Tfh formation in rapamycin-treated mice was due to lower GC B cell responses that are essential for Tfh generation. Additionally, we found that rapamycin had minimal effects on B cell responses activated by lipopolysaccharide (LPS), which stimulates B cells in an antigen-independent manner, suggesting that rapamycin specifically inhibits B cell responses induced by B cell receptor stimulation with antigen. Together, these findings demonstrate that mTOR signals play an essential role in antigen-specific humoral immune responses by differentially regulating B cell and CD4 T cell responses during acute viral infection and that rapamycin treatment alters the interplay of immune cell subsets involved in antiviral humoral immunity. IMPORTANCE: mTOR is a serine/threonine kinase involved in a variety of cellular activities. Although its specific inhibitor, rapamycin, is currently used as an immunosuppressive drug in transplant patients, it has been reported that rapamycin can also stimulate pathogen-specific cellular immunity in certain circumstances. However, whether and how mTOR regulates humoral immunity are not well understood. Here we found that rapamycin treatment predominantly inhibited GC B cell responses during viral infection and that this led to biased helper CD4 T cell differentiation as well as impaired antibody responses. These findings suggest that inhibition of B cell responses by rapamycin may play an important role in regulation of allograft-specific antibody responses to prevent organ rejection in transplant recipients. Our results also show that consideration of antibody responses is required in cases where rapamycin is used to stimulate vaccine-induced immunity.
Assuntos
Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Interações Hospedeiro-Patógeno/imunologia , Imunidade Humoral , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Animais , Apoptose/efeitos dos fármacos , Subpopulações de Linfócitos B/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Centro Germinativo/imunologia , Transplante de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/metabolismo , Imunização , Memória Imunológica , Imunomodulação/efeitos dos fármacos , Camundongos , Camundongos Transgênicos , Transdução de Sinais , Sirolimo/farmacologia , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Transdução Genética , Viroses/imunologia , Viroses/metabolismoRESUMO
During chronic viral infections and in cancer, T cells become dysfunctional, a state known as T cell exhaustion. Although it is well recognized that memory CD8 T cells account for the persistence of CD8 T cell immunity after acute infection, how exhausted T cells persist remains less clear. Using chronic infection with lymphocytic choriomeningitis virus clone 13 and tumor samples, we demonstrate that CD8 T cells differentiate into a less exhausted TCF1high and a more exhausted TCF1low population. Virus-specific TCF1high CD8 T cells, which resemble T follicular helper (TFH) cells, persist and recall better than do TCF1low cells and act as progenitor cells to replenish TCF1low cells. We show that TCF1 is both necessary and sufficient to support this progenitor-like CD8 subset, whereas cell-intrinsic type I interferon signaling suppresses their differentiation. Accordingly, cell-intrinsic TCF1 deficiency led to a loss of these progenitor CD8 T cells, sharp contraction of virus-specific T cells, and uncontrolled viremia. Mechanistically, TCF1 repressed several pro-exhaustion factors and induced Bcl6 in CD8 T cells, which promoted the progenitor fate. We propose that the TCF1-Bcl6 axis counteracts type I interferon to repress T cell exhaustion and maintain T cell stemness, which is critical for persistent antiviral CD8 T cell responses in chronic infection. These findings provide insight into the requirements for persistence of T cell immune responses in the face of exhaustion and suggest mechanisms by which effective T cell-mediated immunity may be enhanced during chronic infections and cancer.
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Studies have established a role for T cells in resolving persistent viral infections, yet emerging evidence indicates that both T and B cells are required to control some viruses. During persistent infection, a marked lag or failure to generate neutralizing antibodies is commonly observed and likely contributes to an inability to control certain pathogens. Using lymphocytic choriomeningitis virus (LCMV) as a model, we have examined how a persistent viral infection can suppress neutralizing humoral immunity. By tracking the fate of virus-specific B cells in vivo, we report that LCMV-specific B cells were rapidly deleted within a few days of persistent infection, and this deletion was completely reversed by blockade of type I interferon (IFN-I) signaling. Early interference with IFN-I signaling promoted survival and differentiation of LCMV-specific B cells, which accelerated the generation of neutralizing antibodies. This marked improvement in antiviral humoral immunity did not rely on the cessation of IFN-I signaling in B cells but on alterations in the virus-specific CD8+ T cell response. Using two-photon microscopy and in vivo calcium imaging, we observed that cytotoxic T lymphocytes (CTLs) productively engaged and killed LCMV-specific B cells in a perforin-dependent manner within the first few days of infection. Blockade of IFN-I signaling protected LCMV-specific B cells by promoting CTL dysfunction. Therapeutic manipulation of this pathway may facilitate efforts to promote humoral immunity during persistent viral infection in humans. Our findings illustrate how events that occur early after infection can disturb the resultant adaptive response and contribute to viral persistence.
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This overview highlights how the high-energy ultraviolet or visible light required to drive photochemical reactions can be overcome by integrating the chromophores into supramolecular structures containing upconverting nanoparticles with trivalent lanthanide dopants (such as Tm(3+) and Er(3+)). These nanoparticles are particularly interesting systems because they absorb multiple photons of near infrared light and convert them into higher-energy light which is emitted in the ultraviolet and visible regions of the electromagnetic spectrum. The upconverting nanoparticles effectively act as nanoscopic 'light bulbs', and in this way, less damaging near infrared light can be used to trigger photochemical reactions for use in imaging and small molecule release. Several examples of how this phenomenon is being used in photochemistry will be presented with the focus being on self-assembled supramolecular systems, some of which are being used in cells and small animals.
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In this protocol, we first describe a procedure to synthesize lanthanide doped upconverting nanoparticles (UCNPs). We then demonstrate how to generate amphiphilic polymers in situ, and describe a protocol to encapsulate the prepared UCNPs and different organic dye molecules (porphyrins and diarylethenes) using polymer shells to form stable water-dispersible nanoassemblies. The nanoassembly samples containing both the UCNPs and the diarylethene organic dyes have interesting photochemical and photophysical properties. Upon 365 nm UV irradiation, the diarylethene group undergoes a visual color change. When the samples are irradiated with visible light of another specific wavelength, the color fades and the samples return to the initial colorless state. The samples also emit visible light from the UCNPs upon irradiation with 980 nm near-infrared light. The emission intensity of the samples can be tuned through alternate irradiation with UV and visible light. Modulation of fluorescence can be performed for many cycles without observable degradation of the samples. This versatile encapsulation procedure allows for the transfer of hydrophobic molecules and nanoparticles from an organic solvent to an aqueous medium. The polymer helps to maintain a lipid-like microenvironment for the organic molecules to aid in preservation of their photochemical behavior in water. Thus this method is ideal to prepare water-dispersible photoresponsive systems. The use of near-infrared light to activate upconverting nanoparticles allows for lower energy light to be used to activate photoreactions instead of more harmful ultraviolet light.
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T follicular helper (TFH) and T helper 1 (Th1) cells generated after viral infections are critical for the control of infection and the development of immunological memory. However, the mechanisms that govern the differentiation and maintenance of these two distinct lineages during viral infection remain unclear. We found that viral-specific TFH and Th1 cells showed reciprocal expression of the transcriptions factors TCF1 and Blimp1 early after infection, even before the differential expression of the canonical TFH marker CXCR5. Furthermore, TCF1 was intrinsically required for the TFH cell response to viral infection; in the absence of TCF1, the TFH cell response was severely compromised, and the remaining TCF1-deficient TFH cells failed to maintain TFH-associated transcriptional and metabolic signatures, which were distinct from those in Th1 cells. Mechanistically, TCF1 functioned through forming negative feedback loops with IL-2 and Blimp1. Our findings demonstrate an essential role of TCF1 in TFH cell responses to viral infection.
Assuntos
Centro Germinativo/imunologia , Fator 1-alfa Nuclear de Hepatócito/imunologia , Memória Imunológica , Coriomeningite Linfocítica/imunologia , Vírus da Coriomeningite Linfocítica/imunologia , Células Th1/imunologia , Fatores de Transcrição/imunologia , Transferência Adotiva , Animais , Diferenciação Celular , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Cruzamentos Genéticos , Retroalimentação Fisiológica , Regulação da Expressão Gênica , Centro Germinativo/patologia , Centro Germinativo/virologia , Fator 1-alfa Nuclear de Hepatócito/genética , Interações Hospedeiro-Patógeno , Imunofenotipagem , Interleucina-2/genética , Interleucina-2/imunologia , Coriomeningite Linfocítica/genética , Coriomeningite Linfocítica/patologia , Coriomeningite Linfocítica/virologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fator 1 de Ligação ao Domínio I Regulador Positivo , Receptores CXCR5/genética , Receptores CXCR5/imunologia , Transdução de Sinais , Células Th1/patologia , Células Th1/transplante , Células Th1/virologia , Fatores de Transcrição/genética , Transcrição GênicaRESUMO
Viral infections induce the differentiation of naive CD4 T cells into two distinct lineages, Th1 cells and T follicular helper (TFH) cells. Two recent studies demonstrated that the microRNA cluster miR-17-92 selectively promotes CD4 TFH responses. However, we show in this study that miR-17-92 expression is required for the clonal expansion of both virus-specific Th1 and TFH cells. Upon viral infection, miR-17-92-deficient CD4 T cells showed impaired clonal expansion and subsequent memory formation. Although miR-17-92 deficiency impaired the clonal expansion of both Th1 and TFH cells, the expansion of Th1 cells was more affected. Overexpression of miR-17-92 in CD4 T cells resulted in increased expansion of both virus-specific Th1 and TFH cells but selectively enhanced the Th1 response. Taken together, our data suggest that miR-17-92 is necessary for both Th1 and TFH cells to respond efficiently to viral infections and that the Th1 response is more sensitive to the level of miR-17-92 expression.
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Seleção Clonal Mediada por Antígeno/imunologia , MicroRNAs/genética , Infecções por Retroviridae/imunologia , Células Th1/imunologia , Animais , Proliferação de Células , Memória Imunológica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , MicroRNAs/biossínteseRESUMO
The water-insolubility of a potentially versatile photoresponsive 'turn-on' fluorescence probe was overcome by incorporating it into a nano-assembly containing an upconverting nanoparticle wrapped in an amphiphilic polymer. The appeal of the nano-system is not only in the ability to turn "on" and "off" the fluorescence from the organic chromophore using UV and visible light, it is in the fact that the nanoparticle acts as a static probe because it emits red and green light when excited by near infrared light, which is not effected by UV and visible light. This dual-functioning emission behaviour was demonstrated in live organisms.
Assuntos
Caenorhabditis elegans/metabolismo , Corantes Fluorescentes , Nanopartículas/química , Imagem Óptica , Raios Ultravioleta , Animais , Caenorhabditis elegans/citologia , Corantes Fluorescentes/química , Corantes Fluorescentes/farmacologiaRESUMO
Sun block for nanoparticles: Unintentional photorelease triggered by UV light is a problem in photodynamic therapy. Encapsulating upconverting nanoparticles containing photoswitches in a UV-blocking amphiphilic polymer shuts down the one-photon process and only allows two-photon-driven photochemistry. Thus, UV light is blocked while NIR light can reach the nanoparticle core and trigger photorelease.